It depends on your body and any existing sensitivity. I'm neither lactose intolerant nor gluten sensitive, so when I have a cheat meal and eat both these things, I feel like crap immediately only because I overeat, and everything goes on as usual the next day. Others can get horrible inflammation, bloating, etc.

F 28/5'4/100 lbs

"I'm not a psychopath, I'm a high-functioning sociopath; do your research."

I've only given up dairy for a week, so nothign there. But I don't eat grains (gave up in August) and the 3 times I accidentally ingested some, I got the tension headache from hell. Pain relief did nothing, I just had to live through it. (not a migraine, thankfully)